1. Field of the Invention
This invention relates generally to tools used to complete subterranean wells. More specifically, the invention relates to a device and method for severing or cutting a control line at a remote location.
2. Description of Related Art
Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore has been drilled, the well must be completed before hydrocarbons can be produced from the well. A completion involves the design, selection, and installation of equipment and materials in or around the wellbore for conveying, pumping, or controlling the production or injection of fluids.
To improve the efficiency of hydrocarbon recovery, wells have begun to incorporate more sophisticated equipment. Examples of such equipment, sometimes referred to as intelligent well or smart well equipment, include monitoring devices, such as gauges, control systems, flow control devices, and other devices designed to recover hydrocarbons more intelligently. Typically, these devices communicate with one another and with the surface or to command equipment in the well via control lines. The control lines may be electrical, hydraulic, fiber optic, or any other type of telemetry communication line. They can be used for the conveyance of fluids for hydraulic actuation or for chemical injection. They may also contain electric wires for power or data transmission.
Often there is a need to separate a section of tubing from a piece of lower equipment in a well to facilitate the removal of the tubing and completion equipment. For example, the tubing may need to be separated from a sand screen completion and pulled from the well. Such a separation is typically done using a safety sub, but other means of separating are well known to those skilled in the art. A safety sub is designed to provide a known separation point within the tubing string, or its attachments, upon the occurrence of a predetermined event, such as the imposition of a force upon the safety sub.
In wells containing control lines, the control lines are generally run into the well in conjunction with the tubing string. If the tubing string is separated and removed from the well and the control line is not also severed in a controlled manner, the act of pulling the tubing from the well will likely cause the control line to stretch and break at some undetermined location. Although such a break may occur at or near the separation point of the tubing from the other downhole equipment, the control line break will likely occur at some point spaced from the tubing separation point. If the break is not at the tubing separation point, there will remain a length of loose control line in the well. If the loose control line is on the equipment or connected to the portion pulled from the well, the control line may catch on other downhole equipment as it passes through the well and damage such equipment or impede the removal of the tubing string. If the loose control line is left on the equipment that is left in the well, the control line may catch and impede equipment in the well or equipment placed in the well at a later time. The control line can become tangled within the wellbore above the remaining equipment in the well. Retrieving the tangled mass of control line can lead to a time consuming and costly recovery effort, often called a xe2x80x9cfishing jobxe2x80x9d, to remove the unwanted control line and regain access to the equipment that is left in the well.
Thus, despite the use of the prior art features, there remains a need for a device to accurately cut the control line proximal the point of tubing separation.
To achieve such improvements, the present invention provides mechanisms and methods for parting a control line.
One embodiment of the present invention is an apparatus comprising a first member, a second member releasably attached to the first member, and a control line shear mechanism. The first and second members can each have a longitudinal bore therethrough and can be moveable in an axial direction to release from one another. The control line shear mechanism may comprise a first shear member attached to the first member and a second shear member attached to the second member, where the first and second shear members are adapted to cooperatively shear a control line as the first and second members separate. The control line shear mechanism may either be integral to the first and second member or may be attached to the first and second members. The first and second members may be releasably attached to each other by a release mechanism, such as a shear element. One form of the control line shear mechanism can comprise a control line passageway within the first and second members. This control line passageway may comprise a recess on the external surface of the first and second members.
Another embodiment of the invention is an apparatus comprising a first tubular member and a second tubular member releasably attached to the first tubular member where the first and second tubular members are moveable in an axial direction to release from one another. The apparatus further comprises a control line shear mechanism comprising a first and second control line shear member where the first control line shear member is attached to the first tubular member, the second control line shear member is attached to the second tubular member and the first and second control line shear members are adapted to cooperatively shear a control line as the first and second tubular members separate.
In still another embodiment a shear sub comprises a first member and a second member releasably attached to the first member. The first and second members define a control line passageway and the control line passageway comprises a pair of shearing blades that are adapted to shear a control line during release. The control line passageway can be positioned at an angle to the direction of release and can comprise a recess on the external surface of the first and second members. The control line passageway may also comprise a passageway enclosed within the first and second members.
Yet another embodiment of the invention is a method that comprises separating a first member from a second member and before or during the separating step, cutting a control line proximal to the point of separation of the first and second members. The first and second members may comprise a safety joint that is used to connect two segments of a tubular string within a wellbore. The safety joint may comprise a control line cutting mechanism that cuts the control line as the first and second members are separated, but the separation of the first member from the second member can be independent from the cutting of the control line.
In an alternative embodiment of the invention a method of completing a well includes providing a tubular string comprising a safety sub where the safety sub comprises a control line cutting mechanism. A control line is attached to the tubular string, the control line being disposed through the control line cutting mechanism, and the tubular string and control line are inserted into the well. The method can further comprise separating the tubular string at the safety sub and cutting the control line with the control line cutting mechanism and can also include the removal of the upper portion of the separated tubular string and the upper portion of the sheared control line from the well.